1. the source or beginning of a stream or river
Usage: often used in plural form ‘headwaters’

Examples

• The headwaters of the Mississippi River are located in northern Minnesota.
• We hiked to the headwaters of the mountain stream.
• The headwaters flow from a natural spring in the forest.
• Environmental protection of headwaters is crucial for downstream water quality.
• The expedition traced the river back to its headwaters.
• Small tributaries join together to form the headwaters of the main river.